Hair is a fascinating feature of the human body. It’s a great way for people to express themselves, and it helps keep dust and dirt away from the face. But it’s also a lot more complex than you might think. In fact, it’s not only made of a fibrous protein called keratin (say: kair-tih-neh-ZAY-shun), but it’s also colored, smoothed by glands that produce oil, and even protects the skin from sunlight and UV rays.
The hair you see on your head and the rest of your body grows from a tiny follicle in your skin. Tiny blood vessels supply the follicle with nutrients, allowing new cells to grow inside it. When the cell at the bottom of the follicle dies, it pushes through the skin’s surface as a hair. The cells in your hair aren’t alive, so they don’t hurt when you cut or shave them.
As you might have guessed, the color of your hair comes from the pigment melanin (say: meh-LAN-een). Melanocytes, specialized cells that produce melanin, live in the base of each hair follicle and inject it into the keratin of each growing hair. This is how hair gets its characteristic shade of brown or blonde.
Each strand of hair has two or three layers, called the cuticle, cortex and medulla. The cuticle is a thin layer of protective cells that covers each hair, while the cortex contains long chains of keratin that give the hair its strength and resilience. The medulla, found only in thicker hair shafts on the head, has a spongy structure that’s reminiscent of bone marrow.
Every hair follicle is attached to a sebaceous gland, which produces lipid-rich oil called sebum (say: sih-BAY-shun). The oil helps the hair follicle stay healthy and moisturize the skin around it. But if the glands pump out too much oil, your hair may look greasy.
Hair isn’t just a cosmetic feature—it’s an important indicator of biological sex, age and ethnic ancestry. It can also have cultural significance. In some cultures, shaving the head or covering it with a scarf is an expression of mourning, and some religious groups have specific rules about how to wear their hair as part of a uniform.
Unlike other mammals, humans have hair on almost all parts of their bodies. In addition to the hair on the head, neck and arms, we have eyebrows, eyelashes and body hair, which is more sparse and usually lighter in color. Hair in the armpits, genital regions and some parts of the trunk and limbs is thicker than that on the head and can be coarser and more heavily pigmented.
It’s not easy to write a character with realistic looking hair, but you can use many different techniques to describe it well. For example, the way your characters move their hair can tell you a lot about them. Try to find ways to make it seem natural and authentic, and be sure to include any accessories your characters might have on their heads, like hats or bandanas.